resolve_user

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden. It implies a read-only lookup but never explicitly states that there are no side effects, nor does it disclose failure behavior (e.g., unknown IDs) or the exact return value. For a simple lookup tool this is acceptable but not thorough.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short sentences with no filler. The primary purpose is front-loaded, and the usage note is relevant and concise. Every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter tool with no output schema, the description covers purpose, usage, and parameter format adequately. The only gap is that it does not specify what the tool returns (e.g., a string, object, or whether both display name and real name are returned). This is minor for the tool's apparent simplicity.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already describes userId as 'U から始まる' (starting with U) at 100% coverage. The description adds no new parameter-level detail; it only gives contextual usage (mentions). Baseline of 3 is appropriate since the schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb (resolve) and a resource (user ID to display name/real name), and provides a concrete use case (converting <@U…> mentions). It clearly distinguishes itself from the sibling tools, which are about channels and threads, not user resolution.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives an explicit scenario for use ('used to convert <@U…> in text to person names'), which tells an agent when to apply it. It does not mention when not to use it or alternatives, but no sibling tool performs this role, so the guidance is adequate.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.